Over many decades, civil engineering endeavors have altered naturally occurring drainage patterns. Transportation and other infrastructure projects are notable examples, typically transforming areas of land from a permeable state capable of absorbing and relatively slowly discharging large volumes of water into impermeable roads, parking lots and the like. Substrates covered over with a layer of concrete or asphalt tend to shed water quite rapidly, causing or exacerbating flooding, and sometimes overloading antiquated wastewater treatment systems in response to precipitation events. In recent years, contractors, engineers and government officials have begun to search for ways to ameliorate undesired effects of certain construction projects on local water drainage and storage capabilities.
One well-known strategy for handling excess water in densely developed regions is the use of retention ponds. It is common for new home construction, particularly in subdivisions, to be accompanied by the creation of man-made retention ponds. Retention ponds create a local storage volume for water which can be released relatively more slowly by evaporation, soil infiltration, etc., than what would occur were precipitation simply allowed to run directly into streams or sewer systems. While relatively simple and straightforward, time and construction expense, as well as safety and even wildlife control issues tend to make retention ponds undesirable in many instances.
Various proposals have also been set forth in relation to pervious construction materials. Concretes, ceramics, and even asphalt paving materials are known which claim to allow water to drain into an underlying substrate. These novel materials may have their place, but are not without drawbacks. On the one hand, construction of traffic bearing surfaces is already a relatively labor intensive process, requiring significant expense. Introducing exotic materials, and often requiring their installation in a fairly precisely prescribed manner and/or under tightly specified environmental conditions, can result in excessive construction costs. On the other hand, such materials may have inherent properties inferior to certain conventional materials such as concrete, asphalt paving material, and brick. There is thus a need for improved strategies to address changes in local water drainage and storage which inevitably result from construction activities.